Google invests in Farmville-maker Zynga: Bad for Facebook?

Google has invested in Facebook‘s leading social video game-maker Zynga, reports Tricia Duryee in All Things Digital. The revelation appeared in a 619-page document filed with the Securities and Exchange Commission Thursday by the maker of Farmville, which is preparing for its initial public offering (IPO). Zynga’s new SEC filing is triple the length of its original filing on July 1, and contains a trove of new information about the company, including a new list of investors.

Google’s name appears at the top of the list, though it is not known the significance of the placement of names on the list as the amount invested was not disclosed in the filing. Other notable investors include Peter Thiel, an early investor in Facebook; investment firms Kleiner Perkins Caufield & Byers and Union Square Ventures; and LinkedIn Chairman and co-founder Reid Hoffman, among others.

Word of Google’s investment in Zynga has been floating around for more than a year. The news was originally reported by Michael Arrington at TechCrunch, who said Google had thrown in around $100 million. (Later reports estimated that the number was closer to $200 million.) According to Arrington’s report, the deal was a “high strategic” move against Facebook. It’s possible that the Zynga investment is part of Google’s plan to build its own social gaming network that would run in conjunction with Google+.

While it might seem easy to view Google’s Zynga investment as a covert attempt to thwart its biggest rival, Facebook, the filing also shows how difficult it will be to slip through the gates of the enemy unharmed. Facebook, the filing shows, has enormous leverage over Zynga, more than was previously assumed.

According to AllThingD‘s Liz Gannes, Zynga must tell Facebook about all new games at least a week before they launch; any game that includes Facebook integration is exclusive to Facebook; and Facebook disproportionately favors Zynga over other game makers.

None of this may surprise anyone who watches these types of things closely. But that doesn’t mean it’s not worth watching at all. In fact, the war between Facebook and Google has only gotten hotter in recent months. And with both companies invested in Zynga, you can bet its quickly approaching IPO will be a major battleground.